The present invention relates to both a method of manufacturing a semiconductor device and a semiconductor device, and in particular, to a technique that is effective when applied to a method of manufacturing a semiconductor device using an SOI (Silicon On Insulator) substrate and the semiconductor device.
Semiconductor devices each using an SOI substrate are currently used as a semiconductor device in which occurrence of a parasitic capacitance can be suppressed. The SOI substrate is a substrate in which a BOX (Buried Oxide) film (embedded oxide film) is formed over a supporting substrate comprised of high-resistance Si (silicon), etc., and a thin layer (silicon layer) mainly including Si is formed over the BOX film. When a MOSFET (Metal Oxide Semiconductor Field Effect Transistor: MOS type field effect transistor) is formed over the SOI substrate, a parasitic capacitance that may be caused in a diffusion region formed in the silicon layer can be reduced. Accordingly, when a semiconductor device is manufactured by using the SOI substrate, the semiconductor device can be expected to be improved in integration density and operating speed and to be free of latch-up, etc.
In Japanese Unexamined Patent Publication No. 2010-4016, it is described that both an SOI region, in which a BOX film and a silicon layer are formed over a substrate, and a bulk silicon region, in which the upper surface of the substrate is exposed by opening the BOX film and the silicon layer to form a sidewall oxide over the side surface of the opening and an epitaxial layer is then formed in the opening, are formed.
Herein, the silicon layer in the SOI region and the epitaxial layer are insulated from each other by the sidewall oxide formed by being deposited over the substrate. The distance between the silicon layer in the SOI region and the epitaxial layer is equal to the thickness of the sidewall oxide.
In Japanese Unexamined Patent Publication No. 2009-267375, it is described that a bulk region and an SOI region, which are separated from each other by an STI (Shallow Trench Isolation), are formed over a substrate. Herein, an SOI layer is formed over the substrate via an oxide, and the upper surface of the substrate is exposed by opening the oxide and the SOI layer to form a sidewall spacer over the side wall of the opening, and an epitaxial layer is then formed in the opening. Thereafter, the STI is formed between the SOI layer and the epitaxial layer by etching the two layers with the use of a silicon nitride layer as a mask.